The present invention relates to pressure regulators, and particularly to the type commonly used for regulating the flow of a fluid, e.g., water in an irrigation system, to maintain a substantially constant outlet pressure.
Fluid pressure regulators generally include a housing having an inlet chamber, an outlet chamber, a connecting passageway connecting the two chambers, and a movable regulator member biassed in one direction to a position fully-opening the passageway but including a pressure-sensor surface exposed to the pressure in the outlet chamber for moving the regulator member in the opposite direction to restrict the passageway in response to the outlet pressure, and thereby to maintain the outlet pressure at a predetermined regulated value. Many different constructions are known, but as a rule the regulator member in the known constructions begins to move to restrict the passageway before the outlet pressure reaches the predetermined regulated value. Thus, if the inlet pressure is below or substantially equal to the desired regulated outlet pressure, the regulator nevertheless produces a pressure drop. This is particularly undesirable with respect to low inlet pressures where the pressure drop across the regulator is to be minimized.
An object of the present invention is to provide a fluid pressure regulator of improved construction which minimizes the pressure drop across the regulator particularly at low inlet pressures.